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Essay:Rebuttal to Counterexamples to Relativity (view source)
Revision as of 18:50, January 30, 2012
, 18:50, January 30, 2012Add 26
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26: ''Relativity requires that anything traveling at the speed of light must have mass zero, so it must have momentum zero. But the laws of electrodynamics require that light have nonzero momentum.''
:This seems to be another basic misunderstanding of relativity, from someone who gave up halfway through the textbook. Newtonian momentum (p = mv) does certainly indicate that a body with zero mass (''m'') must have zero momentum whatever its velocity (''v''). However, the relativistic equation for momentum is:
::<math> p = \gamma m_0v\,</math>
:where ''m''<sub>0</sub> is the [[invariant mass|rest mass]] of the object and ''γ'' is the Lorentz factor, given by
::<math>\gamma = \frac{1}{\sqrt{1 - (v/c)^2}}\,,</math>
:where ''c'' is the [[speed of light]].
:For the case of a photon, where rest mass is zero and ''v'' is equal to ''c'', this gives ''p'' as zero divided by zero - an undetermined value.
:However, with the substitution of the famous E=mc<sup>2</sup>, where E is the energy of the body, the momentum equation can be rearranged to:
::<math>pc = \sqrt{E^2 - m_0^2c^4}</math>
:With a photon of zero rest mass, this gives:
::<math>p = E/c\,</math>
:Finally, substituting Planck's Equation for the energy of a photon <math>E = hf\,</math> where ''h'' is [[Planck's Constant]] and ''f'' is the frequency of the photon, we get the familiar (and experimentally demonstrated) value for a photon's momentum of:
::<math>p = hf/c = h/\lambda\,</math>
:where <math>\lambda</math> is the photon's wavelength.<ref>http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/relmom.html</ref>
27: ''Relativity requires different values for the inertia of a moving object: in its direction of motion, and perpendicular to that direction. This contradicts the logical principle that the laws of physics are the same in all directions.''
27: ''Relativity requires different values for the inertia of a moving object: in its direction of motion, and perpendicular to that direction. This contradicts the logical principle that the laws of physics are the same in all directions.''